• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.69-70
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• 2020

Accidents in the construction industry are very high compared to other industries, and the number is also increasing steeply every year. Relevant studies were limited for solving the problems. The purpose of this study is to develop a comprehensive risk prediction process for personnel deployed at construction sites on safety management. First of all, the variables were divided into fixed, real-time and working types variables, and the relevant comprehensive data were collected. Second, the probability of a disaster was derived based on the collected data, and weights for each variable were calculated using the dummy regression analysis method using statistical methodology. Lastly, the resulting weighting and disaster probability equation was constructed, and The Final Risk Calculation Formula was developed. The Final Risk Calculation Formula presented in this study is expected to have a significant impact on the establishment of effective safety management measures to prevent possible safety accidents at construction sites

• Nuclear Engineering and Technology
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• 제56권6호
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• pp.2343-2351
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• 2024

Accurately predicting the thermal hydraulic parameters of a transient reactor core under different working conditions is the first step toward reactor safety. Mass flow rate and temperature are important parameters of core thermal hydraulics, which have often been modeled as time series prediction problems. This study aims to achieve accurate and continuous prediction of core thermal hydraulic parameters under instantaneous conditions, as well as test the feasibility of a newly constructed gated recurrent unit (GRU) model based on the soft attention mechanism for core parameter predictions. Herein, the China Experimental Fast Reactor (CEFR) is used as the research object, and CEFR 1/2 core was taken as subject to carry out continuous predictive analysis of thermal parameters under transient conditions., while the subchannel analysis code named SUBCHANFLOW is used to generate the time series of core thermal-hydraulic parameters. The GRU model is used to predict the mass flow and temperature time series of the core. The results show that compared to the adaptive radial basis function neural network, the GRU network model produces better prediction results. The average relative error for temperature is less than 0.5 % when the step size is 3, and the prediction effect is better within 15 s. The average relative error of mass flow rate is less than 5 % when the step size is 10, and the prediction effect is better in the subsequent 12 s. The GRU model not only shows a higher prediction accuracy, but also captures the trends of the dynamic time series, which is useful for maintaining reactor safety and preventing nuclear power plant accidents. Furthermore, it can provide long-term continuous predictions under transient reactor conditions, which is useful for engineering applications and improving reactor safety.

• 해양환경안전학회지
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• 제6권1호
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• pp.111-120
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• 2000

In this study the drift prediction models currently used in search and rescue(SAR) operations are introduced and the basic differences among them are analyzed by comparing the target classification, the treatment of environmental conditions, leeway equations and the determination of search area. In addition the new methods under development including AP98 of U.S. Coast Guard are compared and studied to improve the efficiency of SAR operation.

• 한국안전학회지
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• 제12권3호
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• pp.76-82
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• 1997

Flash points ire used to classify flammable liquids according to their relative flammability. Such a classification is important for the safe handling of flammable liquids which constitute the solvent mixtures. MRSM(modified response surface methodology)-1 and MRSM-2 models we suggested for the prediction of the flash points in the flammable ternary system. By means of this methodology, it is possible to predict the flash points of the flammable mixtures system using computer graphics in the triangular coordinate for the ternary system. The proposed methodology(MRSM) has been tested and compared successfully with previously reported flash points in journal for the ternary system.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2377-2386
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• 2021

To model the atmospheric dispersion of radionuclides released from nuclear accident is very important for nuclear emergency. But the uncertainty of model parameters, such as source term and meteorological data, may significantly affect the prediction accuracy. Data assimilation (DA) is usually used to improve the model prediction with the measurements. The paper proposed a parameter bias transformation method combined with Lagrangian puff model to perform DA. The method uses the transformation of coordinates to approximate the effect of parameters bias. The uncertainty of four model parameters is considered in the paper: release rate, wind speed, wind direction and plume height. And particle swarm optimization is used for searching the optimal parameters. Twin experiment and Kincaid experiment are used to evaluate the performance of the proposed method. The results show that the proposed method can effectively increase the reliability of model prediction and estimate the parameters. It has the advantage of clear concept and simple calculation. It will be useful for improving the result of atmospheric dispersion model at the early stage of nuclear emergency.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2005년도 추계학술발표회 논문집
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• pp.146-151
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• 2005

• 한국안전학회지
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• 제24권1호
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• pp.14-20
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• 2009

Direct numerical simulations(DNS) were performed for the prediction of transient buoyant jet diffusion flames where the Froude numbers(Fr) are 5 and 160, respectively. The thermodynamic and transport properties were evaluated using CHEMKIN package to enhance the prediction performance of the DNS code. The simulated buoyant jet diffusion flame of Fr=5 and 160 showed the transient, dynamic motion well. It was identified that the buoyant jet flames were flickered periodically, and the simulated flickering frequency of the jet diffusion flame of Fr=5 was 12.5Hz, which was in good agreement with the experimental results. The flamelet structures of the buoyant jet diffusion flames could be well understood by comparing the scalar dissipation rates(SDR) and the heat release rates(HRR) of the flames. It was found that the SDR was strongly coupled with the HRR in the buoyant jet diffusion flames.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.39-40
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• 2022

The use of asbestos has been completely prohibited in Korea since 2015. Therefore, nationally, the asbestos demolitions in the building are actively underway. In the process of demolishing asbestos, scattering dust occurs, which poses a risk to human body. These dusts causes fatal disease, and especially there is an increasing concern of safety about construction workers and building users. Until this day, however, only few researches have been conducted on asbestos demolishing process. Accordingly, it is necessary to analyze key factors and to develop a safety prediction model for workers. This study is an early stage of building quantified DB, and aims to actualize the safety problems of asbestos demolishing process using text mining method.

• Nuclear Engineering and Technology
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• 제44권6호
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• pp.561-586
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• 2012

This paper describes a summary of final prediction results by system-scale safety analysis codes during the OECD/NEA/CSNI ISP-50 exercise, targeting a 50% Direct Vessel Injection (DVI) line break integral effect test performed with the Advanced Thermal-Hydraulic Test Loop for Accident Simulation (ATLAS). This ISP-50 exercise has been performed in two consecutive phases: "blind" and "open" phases. Quantitative comparisons were performed using the Fast Fourier Transform Based Method (FFTBM) to compare the overall accuracy of the collected calculations. Great user effects resulting from the combination of the possible reasons were found in the blind phase, confirming that user effect is still one of the major issues in connection with the system thermal-hydraulic code application. Open calculations showed better prediction accuracy than the blind calculations in terms of average amplitude (AA) value. A total of nineteen organizations from eleven countries participated in this ISP-50 program and eight leading thermal-hydraulic system analysis codes were used: APROS, ATHLET, CATHARE, KORSAR, MARS-KS, RELAP5/MOD3.3, TECH-M-97, and TRACE.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.21-27
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• 2013

Construction safety is a predominant hindrance in in-situ workflow and considered an unresolved issue. Current methods used for safety optimization and prediction, with limited exceptions, are paper-based, thus error prone, as well as time and cost ineffective. In an attempt to exploit the potential of BIM for safety, the objective of the proposed methodology is to automatically predict hazardous on-site conditions related to the route that the dozers follow during the different phases of the project. For that purpose, safety routes used by construction equipment from an origin to multiple destinations are computed using video cameras and their cycle times are calculated. The cycle times and factors; including weather and light conditions, are considered to be independent and identically distributed random variables (iid); and simulated using the Arena software. The simulation clock is set to 100 to observe the minor changes occurring due to external parameters. The validation of this technology explores the capabilities of BIM combined with simulation for enhancing productivity and improving safety conditions a-priori. Preliminary results of 262 measurements indicate that the proposed methodology has the potential to predict with 87% the location of exclusion zones. Also, the cycle time is estimated with an accuracy of 89%.